The present invention relates to fume extraction and filter apparatus and, more particularly, to a portable fume extraction and filter apparatus.
It is common to provide fume extraction apparatus to remove fumes from workstations at which fumes tend to be generated, such as chemical, soldering, and other workstations. Fume extraction apparatus are provided in several categories. One category of fume extraction apparatus is occasionally referred to as a tip extraction apparatus typically used in applications such as soldering for removing solder fumes substantially at their source. In tip extraction apparatus, a vacuum draws air through a small diameter tube attached to the tip of, for example, a hand-held soldering iron. Tip extraction apparatus are primarily useful for applications in which relatively small amounts of fumes are generated.
Another category of fume extraction apparatus is an arm extraction system in which air is drawn from a workstation through a relatively large diameter duct. Arm extraction systems come in a range of sizes but, as a general rule, pull large volumes of air away from workstations. The arms are typically adjustable to adapt to specific fume extraction needs.
Smaller arm extraction systems typically include an arm connected to a remote vacuum and filter apparatus. In smaller arm extraction systems, it has, in the past, been difficult to achieve desired volume flow rates and adequate pressures required for adequate filtration without making the systems excessively bulky and noisy. Prior art remote arm extraction systems are either so large that they must be provided with a wheeled cart to permit moving the systems from one location to another, or too ineffective for many fume extraction uses.
Larger arm extraction systems typically include an arm or stationary hood at the workstation connected by ductwork to a remote vacuum arrangement. The vacuum arrangement is typically highly oversized to permit use of a single vacuum and filter apparatus for multiple workstations, and to permit modification of the fume extraction apparatus to include additional ductwork for further workstations. Benefits of the larger apparatus include the ability of the apparatus to draw large volumes of air through high efficiency filters, and remote positioning of noise making components such as blower assemblies and motors to minimize the noise level at the remote work area.
An obvious drawback to the fume extraction apparatus with remote vacuum and filter arrangements is that they are not conveniently adaptable to different situations. For example, it is often necessary to extract fumes from a location remote from the arm or stationary hood. Without providing the extensive ductwork necessary to connect up to the vacuum, the fume extraction apparatus is substantially useless in such situations. Obviously, it is not always possible or practical to provide ductwork for fume extraction in all situations.
Another drawback to apparatus with remote vacuum and filter arrangements is that they tend to be inefficient. Because the vacuum is typically oversized to permit expansion of the fume extraction apparatus, the vacuum is rarely optimally sized for a particular application. As a result, energy is wasted, and more expensive equipment is used than is necessary. Moreover, because most conventional fume extraction apparatus include AC motors designed to operate at frequencies of 60 cycles/sec. in the U.S. or at frequencies of 50 cycles/sec. in many European countries, they do not perform efficiently when used with power supplies other than those for which they were specifically designed. When used with conventional U.S. power supplies, a two pole AC motor will be limited to operating at 3600 rpm. While AC motors can be operated at higher speeds when provided with specially adapted variable frequency power supply that provide power at higher frequencies than conventional power supplies, this adds undesirable expense to systems incorporating AC motors. It is desirable to provide a portable fume extraction apparatus that is capable of operation at high speeds without the need for providing specially adapted variable frequency power supply.
Yet another drawback to apparatus with remote vacuum and filter arrangements is that they tend to be quite large, yet may only be needed to extract fumes from a limited area. As a result, space that could be used more profitably for other purposes is wasted for the fume extraction apparatus.
In addition to conventional fume extraction apparatus of the type having ductwork extending between a workstation and a vacuum, various other forms of self-contained fume extraction apparatus are known. Well-known examples of self-contained fume extraction apparatus are the table or floor mounted air cleaners that are occasionally used for extracting non- or minimal hazard fumes such as tobacco smoke from rooms. These apparatus are typically very light duty. They typically have inlets through which air is drawn by a motor-driven blower assembly inside of a housing of the apparatus, a filter through which the air is passed after being drawn inside of the housing, and outlets through which the air is directed after passing through the filter.
Generally speaking, smaller fume extraction apparatus are not suited for applications for which larger fume extraction apparatus with remote vacuums and filters are used. Because their size must be limited, for example, to volumes preferably about 1 ft3 (0.03 m3) or less for convenient portability, to footprints of less than about 100 in2 (0.70 ft2, 0.965 m2) to only minimally obstruction of space, and to heights of no more than about 14xe2x80x3 (0.35 m) for use with many commercially available, prefabricated workbench units, prior to the present invention, small, self-contained fume extraction apparatus required large motors and/or ineffective, low pressure-drop filters to move the comparable volumes of air to the volumes moved by larger fume extraction apparatus per workstation. Typically, as filter effectiveness increases, so does the amount of pressure drop across the filter, and the size of the motor and blower assembly arrangement necessary to overcome the pressure drop increases. As a practical matter, motor size and filter effectiveness have been such limiting characteristics of smaller, self-contained fume extraction apparatus that, when built in any conveniently portable size, they simply are incapable of providing a fume extraction and filtering effect comparable to that capable of being provided by conventional stationary fume extraction apparatus.
Another drawback to known self-contained fume extraction and filtering apparatus is that, when of sufficient size to move air in volumes per unit time comparable to the volumes moved by conventional stationary apparatus at a single workstation, the self-contained apparatus tend to be quite noisy. The noise is typically a result of the operation of a large motor and rotation of components of the blower assembly. Because the self contained fume extraction and filtering apparatus are intended to be located where the people using them are also located, noise levels must be kept low. As a consequence of this aspect, most self-contained fume extraction and filtering apparatus are sufficiently small so that operation of the motor and rotation of the blower assembly components keeps noise at an acceptably low level. Because motor size and blower assembly speeds or sizes are limited, these structures have the effect of limiting the amount of air that can be drawn through the apparatus and the effectiveness of the filter that can be used.
No fume extraction apparatus prior to the present invention is known that is conveniently portable as well as capable of drawing a sufficient volume of air from a workstation and through a highly effective filter. It is desirable to provide a fume extraction and filtering apparatus that is conveniently portable and capable of drawing a sufficient volume of air from a workstation and through a highly effective filter. It is, moreover, desirable to provide such a self-contained fume extraction and filtering apparatus that operates at sufficiently low noise levels to be located at a workstation. Embodiments of the present invention permit providing a portable and self-contained apparatus usable with highly effective filters, and capable of operation at low noise levels as compared with prior art apparatus capable of filtering comparable volumes of air.
According to one aspect of the present invention, a fume extraction and filter apparatus includes a housing including a base and a top portion connected to a top side of the base. The base includes an inlet in a side thereof, the inlet leading into the housing and being in flow communication with an outlet in the top portion. A motor is disposed in the housing. A blower assembly is disposed in the housing and drivable by the motor to draw air into the inlet and cause the air to exit through the outlet. A filter is disposed in the housing between the inlet and the outlet and is arranged to filter air drawn in the inlet before the air exits through the outlet.
According to another aspect of the present invention, a fume extraction and filter apparatus assembly includes a fume extraction and filter apparatus and a duct assembly. The fume extraction and filter apparatus includes a housing including a base and a top portion connected to a top side of the base. The base includes an inlet in a side thereof, the inlet leading into the housing and being in flow communication with an outlet in the top portion. A motor is disposed in the housing. A blower assembly is disposed in the housing and drivable by the motor to draw air into the inlet and cause the air to exit through the outlet. A filter is disposed in the housing between the inlet and the outlet and is arranged to filter air drawn in the inlet before the air exits through the outlet. The dust assembly is attachable to the base.
According to yet another aspect of the present invention, a fume extraction and filter apparatus includes a housing including a side wall having an inlet opening extending from a point above an open bottom of the housing to the bottom of the housing and an inlet leading into the housing and in flow communication with an outlet proximate a top of the housing. The apparatus further includes a motor disposed in the housing, a blower assembly disposed in the housing and drivable by the motor to draw air into the inlet and cause the air to exit through the outlet, and a filter disposed in the housing between the inlet and the outlet and arranged to filter air drawn in the inlet before the air exits through the outlet.